Urusovite is a rare copper aluminum arsenate found primarily in the fumarole deposits of the Tolbachik volcano in Russia. It typically appears as small, delicate tabular or acicular crystals associated with other secondary copper minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Urusovite

Hardness: 3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this urusovite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch urusovite with a known reference. Urusovite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Urusovite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Urusovite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular to acicular crystals.

Often confused with

Urusovite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Lammerite

Mohs 3.5

How to tell apart: Streak differs — Urusovite leaves white, Lammerite leaves light green.

Compare →

Often found alongside urusovite

Minerals reported to co-occur with urusovite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: CuAlAsO₅
Mohs hardness: 3
Density: 4.27 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Tabular to Acicular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarole Deposits of Volcanic Systems
Typical price: $100-500 per specimen

Where rockhounds find urusovite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarole deposits of volcanic systems country — that is the host setting where urusovite typically forms. If you start seeing lammerite, tenorite, hematite in float, you are in the right ground. Field specimens usually show a tabular to acicular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify urusovite?+

Mohs hardness is 3. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is urusovite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is urusovite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is urusovite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic; handle with care and avoid inhalation of dust or ingestion. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like urusovite?+

Urusovite is most often confused with Lammerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with urusovite?+

Urusovite commonly co-occurs with Lammerite, Tenorite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does urusovite form in?+

Urusovite typically forms in fumarole deposits of volcanic systems. Working float back to the host body is the standard way to chase a fresh occurrence.

What is urusovite used for?+

Urusovite is used in collector.

Find urusovite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.